I usually find myself asking the opposite when I am hiring new developers: if this person only knows React - are they even a developer??

Unlike Angular and Vue, React reinforces bad design patterns since the view and logic of a component are rarely separated, and this makes it difficult and messy to do team development.

For example, I recently hired a "React only" dev who seemed hungry enough to learn other things. Unfortunately, they quit after a week without contributing any reasonable commits. The final straw seemed to be a lack of willingness to understand proper MVC.

This was obviously an extreme case, but I've experienced similar things before among young devs of our current generation. Unfortunately, the same things that make React easy to learn mean many new developers won't bother learning the reasons behind the decisions that power React or how to use web components without React.

In our current epoch, it's important to learn how web components work, but the framework you use to achieve this shouldn't matter, and there should be some emphasis on learning how web components work at their most basic and without any framework (W3C spec).

“Unlike Angular and Vue, React reinforces bad design patterns since the view and logic of a component are rarely separated, and this makes it difficult and messy to do team development.”
Spot on!! Not to mention how the react community is...not the most welcoming and accepting of other approaches.